Rarely, chickenpox during pregnancy can cause complications both for the pregnant woman and the unborn baby. In the UK, it’s estimated that chickenpox causes complications for about three in every 1,000 pregnancies.
It is also rare to get chickenpox when you’re pregnant. Most pregnant women who get chickenpox recover, with no adverse effects for the baby.
When to get medical advice
You should seek advice from your GP or midwife immediately if you’re pregnant and:
- you think you may have chickenpox, or
- you know that you haven’t had chickenpox, or you’re not sure, and you’ve been near someone with chickenpox (even if you have no rash or other symptoms).
You should also contact your GP or midwife immediately if you get chickenpox within seven days of giving birth.
Complications that can affect pregnant women
You have a higher risk of developing complications from chickenpox when you’re pregnant if you:
- smoke,
- have a lung condition, such as bronchitis or emphysema,
- are taking steroids, or you have taken steroids during the previous three months, or
- are more than 20 weeks pregnant.
Up to 1 in 10 pregnant women with chickenpox develop pneumonia (inflammation of the lungs).
Other rare complications can include inflammation of some parts of the body. For example:
- the brain (encephalitis),
- the liver (hepatitis),
- the heart muscle (myocarditis),
- the kidneys (glomerulonephritis),
- the appendix (appendicitis), and
- the pancreas (pancreatitis).
Very rarely, complications resulting from chickenpox during pregnancy can be fatal.
Complications that can affect the unborn baby
There is a small risk that chickenpox during pregnancy can cause complications for your unborn baby. These complications vary, depending on how many weeks pregnant you are when you get chickenpox.
Chickenpox during the first 13 weeks of pregnancy does not appear to increase the risk of miscarriage.
However, if an unborn baby is infected with chickenpox in the first 20 weeks of pregnancy, there’s a small risk that they can develop a rare condition called foetal varicella syndrome (FVS). Research has shown that less than 1% of unborn babies were affected by FVS when their mothers had chickenpox while pregnant.
FVS can cause serious birth defects. For example:
- scarring of the skin,
- eye defects, such as cataracts, which cause the lens in the eye to cloud over,
- shortened limbs, and
- brain damage.
Complications that can affect the newborn baby
If you get chickenpox after week 37 of your pregnancy, your baby is at risk of being born with chickenpox. The risk of your baby being born early (prematurely) is also slightly increased.
If you get chickenpox seven days before or after giving birth, your baby may develop a severe type of chickenpox.
If a newborn baby comes into contact with chickenpox or develops the condition, they may need treatment. For more information, see How is chickenpox treated during pregnancy?
In a very small number of cases, severe chickenpox can be fatal.
Further information:
